The Svalbard Global Seed Vault could be mistaken for a set piece from a futuristic Stanley Kubrick film. It juts out of the side of a mountain in Svalbard – a remote Norwegian archipelago located near the North Pole – and in the eternal darkness of the high north’s winter, it glows an eerie, pale blue. It’s during those cold months that scientists choose to load their precious cargo into the vault: the seeds of 825,000 crop plants, and counting.

Also called the “Doomsday Vault”, the facility is designed as a safe guard against those plants’ extinction – many of them essential food. In principle, these crops could prevent humanity’s demise should a global catastrophe occur.

Due to the cold temperatures within the mountain, the vault’s electricity could fail for decades before the seeds perished. The seeds come from all over – the US, Russia, North Korea and beyond – with no regard for political boundaries. “The seeds are all getting along fine, there’s been no fighting yet,” jokes Cary Fowler, an agriculturalist who designed the seed vault and is currently head of its advisory council, and is also a senior advisor to the Global Crop Diversity Trust.

“I think it would be difficult to tell the history of human kind without reference to what’s in that room,” Fowler continues. “These varieties are survivors, they are the ones our ancestors deemed worthy of saving.” Not all things we eat have been so well preserved, however. Throughout history, foods have ebbed and flowed in popularity and abundance, and few have even disappeared. Compared to historic records, 86% of apple varieties grown in the US alone are gone, for example. Old Cornish cauliflowers are extinct, as is the Ansault pear, which pear experts back in the 19th Century described as having a deliciously buttery flavour.

How does a perfectly delicious food begin the march toward extinction? And what is being done to tackle the problem?

We tend to think that a tomato is a tomato, a carrot a carrot, but over the years, farmers have introduced new genetic iterations of both crop and livestock. The wheat used to make bread today, for example, is different than the wheat used 20 years ago in that same recipe. Moreover, just like dogs, there can be many different of breeds – or in the case of crops, varieties – within a single species.

But mass-production in farming has caused a homogenisation of certain foods. “People started using just a couple of breeds for whatever they’re doing – meat, milk, eggs or fibre – in order to get the same sized animals to fit on an assembly line for processing and transportation and – more importantly – to make them grow as quickly as possible,” explains Ryan Walker, marketing and communications manager at the US-based Livestock Conservancy. “Agriculture today is all a numbers game.”

In North America, for example, myriad cattle varieties used to be raised. Today, a single breed – Holstein Friesians – account for 90% of dairy cattle raised in the US, and another 4% are Jersey cattle. All other dairy breeds occupy the remaining 6% sliver.

This change was especially pronounced in the US, but it also took place (and is still taking place) around the world. Today, around 20% of the world’s 8,000 livestock breeds – which include a dozen animals ranging from cows to sheep to ducks to rabbits – are in danger of extinction.

So what’s the rarest food source? It’s difficult to answer, simply because there are so many of them, but there are some strong contenders. In the crops section, some ancient apples in the US grow on a single specimen tree. Others, such as the American chestnut and chinquapins – once staples – are now too rare to be marketed. Turning to livestock, only around 150 Arapawa goats exist, while about 90 midget white turkeys – previously thought to be extinct – were just rediscovered in Alabama. Kerry cattle, however, probably take the prize for rarest livestock: just 93 animals still exist.

Many endangered varieties are unique to a single local region, having never expanded beyond that community’s confines. When small farms or backyard operations shutter or decide to switch to conventional breeds, the local varieties disappear. As a result, compared to pre-1900, about 75% of global farmed plant diversity is gone. For all of the diversity stored within the Seed Vault, many more strains have gone extinct, and more still are on the verge of extinction. “If we don’t grow it, we lose it,” says Richard McCarthy, executive director of Slow Food USA. “And we’ve lost so many crops already.”

So why does it matter if a few varieties of kale and obscure breeds of pigs fall by the wayside?

The arguments for preserving food diversity overlap with those for preserving ecological diversity in the wild. The planet is constantly in a state of flux – now, more so than ever. The climate is warming and weather patterns are shifting. Plants, too, will need to change in order to keep up. But domesticated crops are at an exceptional disadvantage. Their evolution is largely in our selective hands, and we’ve tailored them toward profit-favouring traits such as high yield and durability rather than adaptability. “When a new pest, disease or drought comes, do you want a crop that is pest and disease resistant and drought tolerant, or do you want to just put more chemicals on crops and increase irrigation?” Fowler poses. “The choice seems pretty clear to me.”

“Diversity,” he continues, “is the most effective, easiest, cheapest and most sustainable way to help agriculture adapt to change.”

When we put all of our eggs (or seeds, or animals) in one diversity basket, it leaves that system open to vulnerabilities. The Irish potato famine is perhaps the most famous example of this. In 1845, much of Ireland’s population was almost completely reliant on a single type of potato, the Irish lumper. When ecological disaster struck, thanks to a virulent crop disease called potato blight, farmers were cornered with no other option. More than a million people died before the blight subsided, and another million were forced to flee their homeland. If a similar scenario replayed today, Fowler predicts “the privileged among us would pay an economic price for that lack of planning and prioritising through higher food cost, but the poor would pay for it with their lives.”

“We look at diversity as an insurance policy,” Walker adds.

Besides ensuring that – come what may with the environment – we’re able to feed humanity in the future, there’s also a cultural argument to be made for preserving food diversity. When the Choctaw Indians were pushed out of their native home in the Southern US in the early 19th Century, they brought Choctaw hogs with them when they relocated to Oklahoma. “The hogs provided sustenance along the way, and when they got to Oklahoma they raised them just like they had been doing back home,” Walker says. “The Choctaw Nation has said that – especially during the Depression – if it wasn’t for the Choctaw hogs, a lot of people would have starved.”

The hogs, however, cannot compete with more industrialized breeds, and now only three people raise the 100 or so animals still in existence. That living piece of history is at risk of being lost.

A town or region’s unique taste of place is also sacrificed when local produce and livestock are replaced with supermarket varieties. Back in the day, fistfights would nearly break out over which tomatoes were better – the ones grown in Mississippi’s red mud, or the Creole tomatoes of New Orleans’ rich earth, McCarthy says. Now, only the studious chefs and dedicated foodies likely know that such things as Djena Lee’s Golden Girl Tomato and Radiator Charlie’s Mortgage Lifter Tomato exist, let alone tell them apart.

McCarthy also cites Louisiana strawberries – Klondykes and Tangis, “sweet and delicious, and highly coveted” – which were forced out of production several decades ago because they didn’t travel well and were too small. “Now, we can get strawberries year round, which look beautiful and taste of nothing,” he says. The older generation notices the difference. “They say things like, ‘I remember how much more I enjoyed life because strawberries tasted of strawberries. I could only get them during a certain time of year, but it was worth waiting for,’” McCarthy says.

A few organisations are pushing back. The Livestock Conservancy, for instance, keeps an ongoing, annually updated priority list of around 200 endangered breeds (commonly referred to as heritage breeds) in the US. The conservancy performs genetic tests to ensure animals are indeed purebred, organises training courses for new farmers and helps owners avoid inbreeding – a serious risk for such small populations of animals. So far, the Conservancy hasn’t lost a single listed heritage animal to extinction, although Walker points out that, globally, 62 breeds went extinct from 2001 to 2007 alone, according to the UN’s Food and Agriculture Organisation.

Slow Food USA, on the other hand, documents and maps traditional, endangered foods and recipes in both in the US and internationally. For example, Sweden has reindeer suovas; Ethiopia has Rira honey; Turkey has Seyez wheat bulgur; and Italy has bitter orange flower water. Slow Food provides support and production standards for local artisan producers, and also creates local flagship foods, which serve as a sort of poster-child for a country or region’s diversity of unique but imperiled edibles. Like India’s tigers and China’s pandas do for wildlife organisations, these foods bring attention to the concept of culinary heritage and conservation.

Awareness about these issues is increasing, at least in developed countries, where local breeds and varieties are beginning to appear on both farm-to-table and high-end restaurant menus, as well as in regular kitchens. “There’s definitely growing interest,” Walker says. “People are starting to value quality more than quantity.”

As for Fowler, when he’s not helping to store seeds in the Svalbard vault, one thing he spends his spare time on is tending to an endangered breed of livestock on his farm in Rhinebeck, New York. There, he keeps buckeye chickens, an old breed – and the only one in the US known to be developed by a woman – that is currently listed as threatened by the Livestock Conservancy. “They’re a lovely chicken breed, very friendly and docile and just beautiful,” Fowler says.

And of course, Fowler and his colleagues have us covered on the long term. If nuclear or climatic disaster ever strikes, the Svalbard vault will be ready to reseed the world with life-supporting crops. While we still have a long way to go before our daily diet is anywhere near as diverse as it was a century ago, knowing that we have essential foods safely tucked away in the high north is a comforting thought, at least.

If you would like to comment on this, or anything else you have seen on Future, head over to our Facebook or Google+ page, or message us on Twitter.